What Is Cryogenic Freezing?
Short for cryogenic freezing, cryo freezing is the act of freezing an object to temperatures below a certain temperature — generally, anything below -150°C counts as cryogenic, though there are varying definitions. At such temperatures, materials behave much differently than at room temperature. Over the past century, we've learned how to harness this behavior to develop new surgical techniques, fuel sources, healthier food preservation, and more. Here's a rundown of some of the common applications of cryogenic freezing.
Uses of Cryogenic Freezing
Cryosurgery
Also called cryoablation, cryosurgery is the removal of abnormal tissue like tumors and warts. By freezing such tissue, it can be easily eradicated and replaced with fresh, healthy tissue.
Cryosurgery can be used for both external and internal tissue. When applied externally, the freezing agent causes the skin to blister, which allows one to peel it off easily and let new skin grow in its place. This agent is generally sprayed or applied with a cotton swab.
Internal cryosurgery uses a cryoprobe, which is a slim probe with a cooled tip that is inserted into the body through a small incision and freezes the tissue upon contact. Once frozen, the tissue is disposed of by the immune system.
As one of the least invasive treatment options available for skin conditions and certain cancers, cryosurgery is ideal for quick recovery and minimal pain.
Whole Body Cryotherapy
Whole Body Cryotherapy is a new, trendy practice often found at spas and other wellness centers. In WBC, one steps into a metal booth that immerses the body in cryogenic temperatures, leaving only the head exposed. Supposedly, the practice can relieve pain, assist in injury recovery, and treat conditions like arthritis, migraines, and even anxiety.
While there is some anecdotal evidence supporting the efficacy of cryotherapy to relieve pain, as of 2016 the U.S. FDA does not recognize it as a valid treatment.
Cryonic Suspension
If you're one of those cynical nerds who likes Futurama, then you're already familiar with the premise of cryonic suspension. But for the uninitiated, here's the idea:
Some people are gambling on the idea that at some point, in the "not-so" to "very distant" future, humanity will figure out how to cure lethal diseases, reanimate the dead, and even reverse aging. So in hopes of extending their lifespans, patients sign up to have their bodies stuck into a cryopreservation chamber immediately after brain death, where they will remain until they can be reanimated and cured. These chambers are cooled by liquid nitrogen that is replenished on a regular basis.
Without the past few decades' advancements in cryofreezing, cryonic suspension would remain fully in the realm of science fiction.
Embryo Cryopreservation
A key part of most in vitro fertilization (IVF) procedures, preserving embryos are one of the most well-known applications for cryogenic freezing. Thanks to all of the advances in cryogenics that have made IVF possible, couples with fertility issues can more easily have children with no side effects to the mother or the child. In fact, according to the Cleveland Clinic, "children born from frozen embryos have no greater rate of birth defects or health problems than children born from embryos that were not frozen."
Thermo Scientific & Revco Freezers
Spaceflight
At cryogenic temperatures, gases like hydrogen liquefy. These condensed gases can be packaged into fuel cells for spacecraft, which burn the gases as they would petroleum. While generating and storing hydrogen is challenging and expensive, its
efficiency and the fact that it doesn't further deplete Earth's shrinking supply of fossil fuels has earned it a place as one of the most common spacecraft fuels worldwide. In fact, liquid hydrogen has become NASA's signature rocket fuel thanks to its efficiency.
Food Preservation
Instead of dousing fresh produce in artificial chemicals to preserve them, many companies simply spray them with liquid nitrogen to absorb the heat from them. By the time the product reaches your kitchen, the liquid nitrogen will have evaporated and pose no threat to anyone.
